import SwiftUI
#if canImport(LCEssentials)
import LCEssentials
#endif

struct AddAddressFormView: View {
    @Environment(\.dismiss) var dismiss
    @State var label = ""
    @State var zipCode = ""
    @State var address = ""
    @State var number = ""
    @State var complement = ""
    @State var neighborhood = ""
    @State var city = ""
    @State var state = ""
    @State var isLoading = false
    @State var isLookingUpZipCode = false
    @State var zipLookupMessage: String? = nil
    @State var lastLookedUpZipCode = ""
    @State var lookedUpLatitude: Double? = nil
    @State var lookedUpLongitude: Double? = nil

    let existingAddress: CustomerAddress?
    let onSave: ([CustomerAddress], Bool) -> Void

    private var isFormValid: Bool {
        !label.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty &&
        normalizeZipCodeForAPI(zipCode).count == 8 &&
        !address.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty &&
        !number.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty &&
        !neighborhood.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty &&
        !city.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty &&
        !state.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty
    }

    var body: some View {
        LCENavigationView {
            content
        }
        .setLeftButton(image: AnyView(AppBackButtonIcon())) { dismiss() }
        .setTitle(text: Text(existingAddress == nil ? "Novo endereço" : "Editar endereço").font(AppTypography.heading2).foregroundStyle(AppColors.textPrimary))
    }

    private var content: some View {
        ZStack {
            AppColors.backgroundLight.ignoresSafeArea()

            ScrollView(showsIndicators: false) {
                VStack(spacing: 0) {
                    VStack(alignment: .leading, spacing: 16) {
                        LoginField(icon: "tag", placeholder: "Ex: Casa, Trabalho", keyboardType: .default, text: $label)
                        LoginField(icon: "mail", placeholder: "CEP", keyboardType: .numberPad, text: $zipCode)
                            .onChange(of: zipCode) { _, newValue in
                                let masked = formatZipCodeBR(newValue)
                                if masked != newValue {
                                    zipCode = masked
                                }

                                let normalized = normalizeZipCodeForAPI(masked)
                                if normalized.count == 8, normalized != lastLookedUpZipCode, !isLookingUpZipCode {
                                    Task {
                                        await lookupAddressByZipCode(normalized)
                                    }
                                }
                            }
                        if isLookingUpZipCode {
                            HStack(spacing: 8) {
                                ProgressView()
                                Text("Buscando endereço pelo CEP...")
                                    .font(.caption)
                                    .foregroundStyle(AppColors.textMuted)
                            }
                            .padding(.horizontal, 6)
                        } else if let zipLookupMessage {
                            Text(zipLookupMessage)
                                .font(.caption)
                                .foregroundStyle(AppColors.textMuted)
                                .padding(.horizontal, 6)
                        }
                        LoginField(icon: "mappin.and.ellipse", placeholder: "Rua / Avenida", keyboardType: .default, text: $address)
                        LoginField(icon: "number", placeholder: "Número", keyboardType: .default, text: $number)
                        LoginField(icon: "plus.app", placeholder: "Complemento (opcional)", keyboardType: .default, text: $complement)
                        LoginField(icon: "square.grid.2x2", placeholder: "Bairro", keyboardType: .default, text: $neighborhood)
                        LoginField(icon: "building.2", placeholder: "Cidade", keyboardType: .default, text: $city)
                        LoginField(icon: "map", placeholder: "Estado (UF)", keyboardType: .default, text: $state)
                            .onChange(of: state) { _, newValue in
                                let normalized = String(newValue.uppercased().prefix(2))
                                if normalized != newValue {
                                    state = normalized
                                }
                            }
                    }
                    .padding(.horizontal, 24)
                    .padding(.bottom, 20)

                    PrimaryButton(title: existingAddress == nil ? "Salvar endereço" : "Atualizar endereço", image: Image(systemName: "checkmark")) {
                        saveAddress()
                    }
                    .padding(.horizontal, 24)
                    .disabled(!isFormValid || isLoading)
                    .opacity((!isFormValid || isLoading) ? 0.5 : 1.0)
                    .tint(AppColors.tertiary)

                    SecondaryButton(title: "Cancelar") {
                        dismiss()
                    }
                    .padding(.horizontal, 24)
                    .padding(.top, 12)

                    Spacer().frame(height: 120)
                }
            }
            .padding(.top, 18)
        }
        .navigationBarBackButtonHidden(true)
        .appHiddenNavigationBar()
        .onAppear {
            populateFromExistingAddressIfNeeded()
        }
    }

    private func saveAddress() {
        guard !isLoading else { return }
        let latLong: [Double]? = {
            if let lat = lookedUpLatitude, let lng = lookedUpLongitude {
                return [lat, lng]
            }
            return nil
        }()

        let newAddress = CustomerAddress(
            id: existingAddress?.id ?? UUID().uuidString,
            label: clean(label),
            address: clean(address),
            number: clean(number),
            complement: optional(clean(complement)),
            neighborhood: clean(neighborhood),
            city: clean(city),
            state: clean(state),
            zipCode: optional(normalizeZipCodeForAPI(zipCode)),
            latLong: latLong,
            isDefault: existingAddress?.isDefault
        )
        isLoading = true
        zipLookupMessage = nil

        Task {
            do {
                let response = try await ApiService().saveCustomerAddress(newAddress, replacingAddressId: existingAddress?.id)
                await MainActor.run {
                    isLoading = false
                    if response.error {
                        zipLookupMessage = response.message ?? "Não foi possível salvar o endereço."
                        SnackbarCenter.shared.show(title: zipLookupMessage ?? "Não foi possível salvar o endereço.", style: .error, icon: "xmark.octagon.fill", duration: 4.0)
                        return
                    }

                    let updatedAddresses = response.result?.addressBook ?? [newAddress]
                    onSave(updatedAddresses, existingAddress != nil)
                    dismiss()
                }
            } catch {
                await MainActor.run {
                    isLoading = false
                    let message = error.localizedDescription
                    zipLookupMessage = message
                    SnackbarCenter.shared.show(title: message, style: .error, icon: "xmark.octagon.fill", duration: 4.0)
                }
            }
        }
    }

    private func populateFromExistingAddressIfNeeded() {
        guard let existingAddress else { return }
        label = existingAddress.label ?? ""
        zipCode = formatZipCodeBR(existingAddress.zipCode ?? "")
        lastLookedUpZipCode = normalizeZipCodeForAPI(zipCode)
        address = existingAddress.address ?? ""
        number = existingAddress.number ?? ""
        complement = existingAddress.complement ?? ""
        neighborhood = existingAddress.neighborhood ?? ""
        city = existingAddress.city ?? ""
        state = String((existingAddress.state ?? "").uppercased().prefix(2))
        lookedUpLatitude = existingAddress.latLong?.first
        lookedUpLongitude = existingAddress.latLong?.dropFirst().first
    }

    private func clean(_ value: String) -> String {
        value.trimmingCharacters(in: .whitespacesAndNewlines)
    }

    private func optional(_ value: String) -> String? {
        value.isEmpty ? nil : value
    }

    @MainActor
    private func lookupAddressByZipCode(_ zip: String) async {
        isLookingUpZipCode = true
        zipLookupMessage = nil
        defer { isLookingUpZipCode = false }

        do {
            let response = try await ApiService().lookupZipCode(zip)
            lastLookedUpZipCode = zip

            guard response.error == false, let result = response.result else {
                zipLookupMessage = response.message ?? "Não foi possível consultar este CEP."
                return
            }

            fillAddressFields(with: result)
            zipLookupMessage = "Endereço preenchido automaticamente."
        } catch {
            zipLookupMessage = "Não foi possível consultar o CEP agora."
        }
    }

    private func fillAddressFields(with result: CepLookupResult) {
        if address.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty {
            address = result.street?.trimmingCharacters(in: .whitespacesAndNewlines) ?? ""
        }
        if neighborhood.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty {
            neighborhood = result.neighborhood?.trimmingCharacters(in: .whitespacesAndNewlines) ?? ""
        }
        if city.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty {
            city = result.city?.trimmingCharacters(in: .whitespacesAndNewlines) ?? ""
        }
        if state.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty {
            state = String((result.state ?? "").uppercased().prefix(2))
        }
        if complement.trimmingCharacters(in: .whitespacesAndNewlines).isEmpty {
            complement = result.complement?.trimmingCharacters(in: .whitespacesAndNewlines) ?? ""
        }
        lookedUpLatitude = result.latitude
        lookedUpLongitude = result.longitude
    }
}